Donald Trump’s victories in five primary elections on Tuesday have given him a claim on the Republican presidential nomination that his party’s establishment can no longer dare to stop, former US Senate Republican adviser Jim Jatras told Sputnik.

WASHINGTON (Sputnik) — Trump won more than 50 percent of the total Republican primary votes in the US states of Pennsylvania, Rhode Island, Delaware, Maryland and Connecticut. In each state, he won more votes than his remaining challengers, Senator Ted Cruz and Ohio Governor John Kasich combined.

"I am almost sure Trump will secure enough delegates to win the party’s presidential nomination on the first ballot at the [Republican] national convention in Cleveland this July," Jatras stated on Wednesday.

Trump’s victories by such wide margins had destroyed any arguments either Cruz or Kasich had hoped to make to be selected instead of him at the Republican Party’s convention in Cleveland, Jatras maintained.

"Trump’s five-state win this week makes it clear even to Republicans for whom he is not their preferred choice that the only alternative to rallying behind him is chaos and a Hillary [Clinton] victory."

Jatras also assessed Cruz’s choice earlier on Wednesday of former Republican presidential candidate Carly Fiorina as his vice presidential running mate was a desperate ploy to try and revive his diminishing campaign.

Usually presidential candidates from either main US political party do not choose their vice presidential partners until they themselves have secured their parties’ nominations.

Also, Fiorina never won even as much as 10 percent of the vote from Republicans in any of the primary contests she entered and never generated any significant support at all, Jatras pointed out.

"Senator Cruz's announcement of Carly Fiorina as running mate appears what it is, an act of desperation."

Jatras also noted that Trump was offering American voters a real choice on foreign as well as domestic policies to break away from widely discredited and unpopular previous positions that had led to costly and unsuccessful wars.

"Trump's speech on foreign policy [on Wednesday] shows that Americans have for the first time in a long while a sober, national-interest based alternative to the disastrous policies of Republican Party neoconservatives and Democratic Party liberal interventionists."

Trump’s foreign policy positions, along with his "America First" trade and immigration policies, would generate huge appeal across the US political spectrum, Jatras concluded.